The present invention relates to installations for the repair and the checking of vehicle bodies, which, for example, have been damaged in an accident, and more particularly, to such installations of the type including a free-standing bench and a pulling tower assembly.
In order to execute a repair, especially by straightening of the pieces of sheet metal of a vehicle, an apparatus including a pulling tower assembly is generally used in conjunction with a bench to which the vehicle is secured by way of suitable clamps or jigs. The pulling tower assembly comprises a base constituted by an elongated member, such as a tubular beam capable of being slid beneath the bench and being equipt with means for clamping onto the frame of the bench. The bench is constituted by a rectangular frame made of two U-shaped and I-shaped metallic side members assembled together by two cross-pieces between the two longitudinal side members. The bench includes clamps for anchoring the body of the vehicle to be repaired, and cross-members which mount assemblies for repairing the vehicle and measuring apparatus.
At one end of the base-forming beam of the pulling tower, there is mounted an arm which is articulated around a horizontal shaft which extends transverse relative to the beam. A chain has one end hooked onto the vehicle body and its other end attached to the arm, which is adapted to be moved around its shaft and exert a traction on the chain, under the action of a hydraulic jack.
The angle of inclination of the articulated arm is adjustable making it possible to achieve a lateral slanting of the arm required to exert a traction under the angle which is most suitable.
A first drawback of the traditional benches, which are secured to the floor of the work space, is their rigidity, which results in the bench conforming to the possible unevennesses of the ground, which can result in measurement errors when the ground on which the rests is not perfectly flat.
In addition, in use, the straightening pulling tower assembly required a very large area especially because of the length of the base-forming beam of the assembly. Taking into account the length of the beam, it is indeed necessary to have available a large space with respect to the bench in order to be able to disengage the pulling tower from the bench and to move it relative to the bench in order to secure it at another point along the bench.
It must further be noted that the length of the pulling tower is further increased to the extent that its base is constituted of two parts such as two elongated beams, disposed in end-to-end relation, and articulated one on the other around a vertical shaft.
French Pat. No. 2 511 272 discloses an apparatus for straightening the chassis and bodies of vehicles, which comprises a bench with a reinforcing nose turned inwardly near its upper edge. That apparatus has an associated pulling tower the fore part of which is in the shape of a forward open stirrup, formed by two horizontal plates intended to be positioned, respectively above and below the frame of the bench, the upper plate being fitted with a hook which engages the reinforcing nose of the frame. That apparatus, however, is not satisfactory because, under conditions when the pulling tower is used, the portion of the pulling tower that is remote from the bench tends to tip upward, a displacement which is unopposed by the elements of the bench. It is thus impossible to obtain a good rigidity of the bench and of the pulling tower.